The present invention relates to a method for mechanically advancing clean cut underground mining galleries of various profiles, as well as to a machine for carrying out the method.
Technology has reached the stage where underground mining galleries are extended by means of full-cut machines. Admittedly such machines are capable of creating a clean cut gallery profile but the profile is limited to a circular shape. Moreover, the dimensions of the profile are determined by the diameter of the full-cut tools. Therefore galleries with different profiles must be made by full-cut machines specific for such profile. However arched, elliptical or substantially rectangular gallery profiles cannot be made with such full-cut machines. Moreover, the technique presents a problem in that simultaneously with the extension of galleries, the gallery supports must be supplied and installed. The reason for this problem is that a full-cut machine occupies a large space in the mining gallery, that is it practically fills the cross-section thereof.
A method is further known in which partial-cut machines are used to extend mining galleries, which machines are capable of creating profiles different from a circular one. The dimensions of such profile are also fairly optional. However, such partial-cut machines are not capable--irrespective of the gallery profile--to produce a sufficiently clean cut gallery profile to make it possible to install the gallery supports. The irregular cutting is e.g. caused by the hydraulic controls of such machines and by the usually relatively long booms, at the ends of which the tools are mounted. The irregularities are made worse by the circumstance that the partial-cut machines cannot be as freely rigged in the mining gallery as one would wish. Furthermore, most partial-cut machines are not capable of making a tangential surface cut on account of the fact that the machines with the attached cutting booms, are positioned in the middle of the gallery. Due to the kinematic of such machines, sawtooth-shaped profiles in the mine gallery walls and therefrom resulting removal of rocks beyond the desired profile cannot be avoided. Such undesirable extended cavities require refilling and result in a distortion of the mine roof support to be set. In addition it is disadvantageous that a relatively large delay in setting the mine roof support cannot be avoided since the latter can be installed only after all the rubble resulting from gallery cutting has been collected and removed. The stability of the geological formations will thereby necessarily detrimentally affected.
Finally, using the old methods and machinery, great difficulties arise in correlating the excavation work and the installation of mine roof supports in such a way to insure that as many different activities as possible may be carried out at the same time. Usually excavation must be stopped while placing the mine roof supports. The progress theoretically possible is thereby greatly impaired.